CHAPTER XXXVIII 



OBSERVATION TREES AND CENSUS RETURNS 



ON most well-managed estates it is now the custom to 

 select and set apart representative rows of trees on 

 various areas. These areas should contain trees of all the 

 different dates of planting. The trees selected are always 

 marked in some distinctive manner, as, for example, with a 

 circle of red paint. A letter A, B or C, etc. is also painted on 

 the first tree next the roadway in each observation row, and the 

 trees in each row numbered in sequence. 



Measurements of the girth of each tree are taken at. a height 

 of 3 feet from the ground every three months and entered on 

 the observation sheets, copies of which should always be sent 

 home to the head offices. The increases in girth should be 

 always carefully noted and compared with the figures for 

 the preceding three months. One-year-old trees are seldom 

 measured in this way for girth. It is generally found that it is 

 the young trees of 10 to 15 inches in girth, 3 feet from the ground, 

 which show the greatest average increase in girth. Such trees, 

 in the Federated Malay States and in Sumatra, generally show 

 an average increase in girth of quite ij- inches every three 

 months. Many add 2 inches or more to their girth during three 

 months. Trees of 18 to 22 inches in girth, 3 feet from the ground, 

 usually add only about i inch to their girth during the same 

 period. 



These are normal figures for normal trees. Loosening the 

 soil all round the roots by digging speeds up increase in girth 

 very markedly. Under such circumstances young trees have 

 added 2j to 3 inches to their girth within a period of three 

 months. This is just another proof of what cultivation can do 

 to improve an estate. 



When trees are being tapped, the tape, being passed round 

 over an excised area of bark, may sometimes give a measure- 



285 



